On the border with Morrowind, the Shadowfen region has had more contact with Tamrielic civilization than most of Black Marsh—due primarily to the activities of the Dunmeri slavers who once operated out of the city of Stormhold. Now the Argonians are back in charge.

It is a fetid mire, often fought over by the Imperial Legion and Dunmer slavers. The ancient city of Stormhold is located here, the source of the devastating (to non-Argonians) Knahaten Flu. Local creatures include giant snakes, fleshflies and wamasu, and diseases such as blood rot, the droops, and swamp fever are quite common. Though the practice of Argonian slavery was abandoned when Black Marsh joined the Ebonheart Pact, rogue Dunmeri slave traders can still be found roaming the marshes. Hist trees and ruined temples can also be found along the winding channels and dank foliage.